Rituximab With or Without Chemotherapy for Anti-MAG Neuropathy: A Retrospective Multicenter Real-World Study
Delmont Emilien1, Cintas Pascal2, Tard Céline3
1Referral Center for Neuromuscular Diseases and ALS, La Timone Hospital, Aix-Marseille University, Marseille, France.
Background And Aims:
In anti-myelin-associated glycoprotein (MAG) neuropathy, the efficacy of rituximab (RTX) is not demonstrated in randomized controlled trials. Combinations of RTX with conventional chemotherapy (immunochemotherapy, ICT) may provide potential benefit, but systematic evaluations are lacking. We aimed to compare the efficacy and safety of RTX and ICT in a multicenter retrospective real-world cohort.
Methods:
Patients with anti-MAG antibody titers > 10 000 Buhlmann titer units (BTUs) were included. Treatment response was defined as an improvement of ≥ 1 point in the Overall Neuropathy Limitation Scale (ONLS) compared to baseline. Propensity score matching was used to account for differences in baseline characteristics between treatment groups.
Results:
A total of 230 patients were included: 150 received RTX and 80 received ICT. Mean follow-up was 4 years (range, 1-20 years). One year after treatment, clinical improvement occurred in 61/147 (41%) patients treated with RTX and 39/78 (50%) treated with ICT (OR = 1.4 [0.8-2.5] p = 0.3). At last follow-up, clinical improvement occurred in 55/150 (37%) patients treated with RTX and 31/80 (39%) treated with ICT (OR = 1.1 [0.6-1.9] p = 0.8). Propensity score matching yielded similar results. Among ICT regimens, dexamethasone-RTX-cyclophosphamide was associated with the highest response rate. RTX induction, 1 g days 1 and 15, seemed superior to four-weekly infusions. Adverse events were more frequent with ICT than with RTX (28% vs. 15%; OR = 2.20 [1.07-4.54], p = 0.02).
Interpretation:
In this cohort, adding chemotherapy to RTX was not associated with greater long-term improvement, despite a higher rate of adverse events. Prospective controlled studies are needed.